1. Field of Invention
The present invention relates to an optical disc drive apparatus, and more particularly, to high-speed reproduction of an optical disc using the optical disc drive apparatus.
2. Description of the Related Art
A conventional optical disc drive apparatus uses a semiconductor laser as a light source of its optical pickup. The power of a semiconductor laser that is used to reproduce data from an optical disc (reproduction power) is typically low. Thus, returned light or changes in the power of the semiconductor laser beam due to variation in the temperature of the semiconductor laser are not negligible. This causes relatively large noise to be generated in reproduction signals of the optical pickup. To reduce such noise in the reproduction signals, a high-frequency current may be superimposed on a laser driving current. The semiconductor laser is stabilized during reproduction of the optical disc by controlling the intensity and frequency of the high-frequency current. As a result, the noise in the reproduction signals is reduced (see, for example, Patent Document 1).
The driving current of the semiconductor laser is set low particularly when data is to be reproduced from a recordable or rewritable optical disc. This sets the reproduction power to such a level that signals recorded on the optical disc are not erased by the energy of the laser beam irradiating the optical disc (see, for example, Patent Document 2).    Patent Document 1: Japanese Unexamined Patent Publication No. H11-54826.    Patent Document 2: Japanese Unexamined Patent Publication No. 2001-14679.